By FARHAD MANJOO

Published: June 1, 2011

TOILET SEATS get a bad rap, says Charles Gerba, an environmental microbiologist at the University of Arizona. Indeed, because of what goes on there, we tend to consider bathrooms — even the most respectable bathrooms — as generally less than sterile. That view, it turns out, is unfair.

From left: Verilux’s sanitizing wand ($70), which is designed for hard surfaces like cutting boards, uses UV rays, as do Honeywell’s air purifier tower ($200) and VIOlight’s cellphone sanitizer ($40).

In numerous studies, Dr. Gerba and his colleagues have found that toilet seats are often one of the least germ-infested areas in your house. Much of the rest of the bathroom, too, isn’t especially toxic. If you’re really worried about germs, look to the kitchen.

“Cutting boards are just terrible,” Dr. Gerba said, by way of example. “There’s 200 times more bacteria on a cutting board than a toilet seat.”

I got to talking to Dr. Gerba — who has been studying the spread of bacteria, viruses and other pathogens in households for so long that many of his colleagues call him Dr. Germ — because lately I’ve had cleanliness on the brain. I’ve been testing several gadgets that promise to reduce or eliminate many household pathogens: devices to sanitize your cellphone, your toothbrush, your bedding, your floors, your countertops, and even the very air circulating through your home.

One by one, I put these gadgets through their paces. But then what? Germs’ power derives from their invisibility. And that’s the trouble with fully evaluating these high-tech germ destroyers — how would I know that they were working well? To find out, I asked Dr. Gerba, who is not paid to endorse any of the products I tested, and he said I’d more or less have to take it on faith. The good news is that we know a lot about sanitizing, but as to claims of a specific product’s effectiveness, firm answers are hard to get without your own lab.

Consider the VIOlight UV Cell Phone Sanitizer, a $40 device that promises to eliminate 99.9 percent of the bacteria and other nasties sitting on your phone. It purports to do so by using a beam of ultraviolet light, which is a specific wavelength of light that, when focused precisely, penetrates and damages the DNA of microorganisms. Dr. Gerba said that ultraviolet-based systems have been used in commercial and industrial sanitizing applications for many years. The technology is now getting small and inexpensive enough to be found in many consumer devices, too. In fact, most of the devices I tested used UV light as their primary cleaning agent.

The cellphone cleaner, a hunk of silver plastic as big as a soap dispenser, is simple to use: Just drop your phone inside and shut the lid. A light on the front blinks on and off to tell you it’s working. After about 5 minutes, the sanitizing is done. When you pull your phone out, it won’t look or smell any cleaner — the sanitizer isn’t meant to remove smudges or stains — but presumably the UV light has killed off everything microscopic.

Presumably: On the one hand, UV light is a proven sanitizer. But on the other I honestly have no idea if this particular cleaner did its job well.

Dr. Gerba added that, with cellphones, it may not matter much. Even if you assume that the sanitizer is decimating the phone’s microscopic inhabitants, it’s unlikely that your phone was covered in anything really dangerous. “Cellphones can get fairly germy, but it’s only your germs,” Dr. Gerba said. “Unless you’re sharing your phone with other people, there’s nothing to worry about.” (Dr. Gerba is asked about the necessity of cellphone sanitizing so often that he has a quip at the ready: “It keeps you from talking dirty.”)

You’re on slightly firmer ground with another VIOlight device — the $30 toothbrush sanitizer. This looks like a standard toothbrush holder, but when you press a button on the front, a UV light shines on the germs on your brushes (the unit holds up to four). According to a 2008 study published in the American Journal of Dentistry, toothbrushes treated with the VIOlight had 86 percent fewer “colony-forming units” — a measure of germs — than toothbrushes that were just rinsed in cold water. The study does note, however, that there’s no proof that a cleaner toothbrush results in better oral health.

UV light can also help with your cutting board, that epicenter of household filth. For this, I tried the CleanWave Sanitizing Wand, a $70 device made by Verilux. The wand looks like a shrunken light saber, and to attack your germs, you can play Luke Skywalker. Turn on the wand, hold one edge against a flat surface — your cutting board, your countertop, your desk — and slowly move it back and forth over the area you’d like to sanitize.

Ryan Douglas, the chief executive of Verilux, said that when he cleans with the wand, he can tell that it’s working. “As you wand over an area, there’s a ‘freshness’ you can smell when the biological material is killed,” Mr. Douglas said.

I confess I smelled nothing of the sort. Still, of all the applications for UV, Dr. Gerba said studies show that it is most effective on hard, nonporous surfaces like cutting boards. Even though I couldn’t tell it was working, there’s a high likelihood that the wand cleaned my cutting board far better than would most other home cleaning products, and it also contained no harmful chemicals. What’s more, as Mr. Douglas pointed out, there’s no way to know that traditional spray cleaners are actually sanitizing, either. I did have one problem with the wand: For safety reasons (UV light can be harmful if you look at it directly), it will work only when you wave it horizontally, with the UV beam pointed downward. That means you can’t use it to sanitize your kitchen walls or your faucet, and must rely on traditional cleaners.

There are two other UV gadgets I tested. The Verilux CleanWave Sanitizing Furniture and Bed Vac ($130) will sanitize soft, plush items that you can’t attack with traditional sanitizing chemicals. Mr. Douglas said that it is especially effective against bedbug and dust-mite eggs. I also ran Honeywell’s HEPAClean UV Antibacterial Air Purifier (about $200) in my bedroom for a few nights. In addition to several layers of filters — which are used in many air purifiers — this unit uses UV lights to kill germs passing through the air. It promises to eliminate 99 percent of such pathogens — but, of course, I had no way to test that.

Besides UV, another high-tech sanitizing method is “super-oxygenated water,” which is used in commercial agriculture. The lotus Home Cleaning System ($219) comes with an electronic base and two vessels for water — one big bowl and one spray bottle. You fill one of the vessels with water, insert it into the base, and turn it on. The water cycles through the base, where it’s hit with an electrical current and forced to take on an extra oxygen molecule. After a few minutes, all the water is converted — and now it’s ready to sanitize. You can fill the bowl with items to sanitize — fruit, vegetables, meat, dishcloths, sponges, baby bottles, pacifiers — or use the spray bottle for general cleaning. It’s harmless, and effective even against stains. But how do you know this product harnesses the proven oxygenating process to actually work well? Once again: You don’t.

That brings me to my favorite sanitizing gadget, the Shark Lift-Away Professional Steam Pocket Mop (about $200). This device works on floors and countertops, and it requires no soaps or other cleaning products. Instead, it uses just water: water in the mop’s chamber is heated and converted into steam, which then shoots into the mop head to clean your floors. I found the mop to be quick and convenient, and it removed stains and left my kitchen floors gleaming. And how did I know it was sanitizing? I saw the steam rising from the tile. That’s good enough for me.